I. Field
The present invention relates generally to data communication, and more specifically to techniques for sending GSM cell broadcast SMS messages in CDMA communication systems.
II. Background
Short Message Service (SMS) is a service that supports the exchange of SMS or short messages between terminals (e.g., cellular phones) and a wireless communication system. These short messages may be point-to-point messages intended for specific terminals or broadcast messages intended for multiple terminals.
SMS may be implemented by various types of wireless communication systems, two of which are code division multiple access (CDMA) systems and time division multiple access (TDMA) systems. A CDMA system may be designed to implement one or more standards such as IS-2000, W-CDMA, IS-95, and so on. A TDMA system may also be designed to implement one or more standards such as Global System for Mobile Communications (GSM). A CDMA system that implements IS-2000 is often referred to as a cdma2000 system.
A network typically refers to a deployment of a system. A CDMA network utilizes a CDMA air interface (e.g., IS-2000, W-CDMA, or IS-95), and a GSM network utilizes a GSM air interface. A network typically further implements a particular mobile networking protocol that allows for roaming and advanced services, with ANSI-41 being commonly used for CDMA networks (except for W-CDMA) and GSM Mobile Application Part (GSM-MAP) being used for GSM and W-CDMA networks. A GSM1x network utilizes a CDMA air interface and implements GSM-MAP, and may be considered as both a CDMA network and a GSM-MAP network.
SMS is network technology dependent, and two SMS implementations have been defined for ANSI-41 and GSM-MAP. Each SMS implementation has different capabilities and utilizes different message types and formats for sending SMS messages. A communication network normally supports either of the two SMS implementations, depending on the underlying network technology. The SMS implementation for ANSI-41 networks is described in TIA/EIA-637-B, entitled “Short Message Service for Wideband Spread Spectrum Systems.” The SMS implementation for GSM-MAP networks is described in documents 3GPP TS 23.038 and TS 23.040. GSM point-to-point (PP) SMS procedures for the terminals are described in GSM 03.40 and 04.11, and GSM cell broadcast SMS procedures for the terminals are described in GSM 03.41 and 04.12. These documents are publicly available and incorporated herein by reference. For simplicity, the SMS implementation for GSM-MAP is referred to as GSM SMS, and the SMS implementation for ANSI-41 is referred to as CDMA SMS.
Although CDMA and GSM are quite different in design, an interworking and interoperability function (IIF) has been defined to allow for communication between these two different types of networks. The result is that improved coverage and performance may be attained for users of the networks. Through the IIF, a GSM mobile user may roam into the coverage area of a CDMA network and can continue to receive service, and vice versa.
A GSM-MAP network may be designed to provide Cell Broadcast SMS (CBS) service. This service periodically broadcast GSM CBS messages to terminals within designated geographic areas. The GSM CBS messages can carry various types of information such as road traffic information, weather information, and so on. Each GSM CBS message includes one or more CBS pages, and each CBS page includes various fields for various attributes of the message. These fields may be used to filter the messages, so that the users can selectively receive only desired messages and filter out undesired ones.
For GSM1x networks and CDMA ANSI-41 networks that interwork with GSM-MAP networks, it is desirable to send GSM CBS messages to terminals over the CDMA air interface. This would then allow the terminals to receive CBS service. However, because the implementations for CDMA SMS and GSM SMS are different, the GSM CBS message and the broadcast message in CDMA SMS have different formats.
There is therefore a need in the art for techniques to send GSM CBS messages in CDMA communication systems.